Automatic train control



3 Sheets-Sheet 1 'r. M. RIGGLE AUTOMATIC TRAIN coNTRoL- FiledvApr'il 29.1924v Qkmw.

ivm

July 5, 1927..

July 5, 19,21., 1,534,557

T. M.'R|GGLE AUTOMATIC TRAIN CONTROL Filed April 29. 1924 s sheets-shet2 .sl +7 f? 54 +9 55 d f'- a a r 9%' l l l INVENTOR. Tf1/@6605 BY 7M,ATTORNEY July 5, 1927.

T. M. RIGGLE AUTOMATIC TRAIN CONTROL I5 Sheets-Sheet 5 Fled- April 29.1924 l INVENTOR. Z'fZ ATTORNEY Patented July 5, 1927.

UNITED STAT-'Es PATENT oFF-ICE.

THOMAS M, RIGGLE, or OAKLAND, CALIronNIAyAssIGNOn To RIeeLn AUTOMATICTRAIN CONTROL COMPANY, or OAKLAND; CALIFORNIA, A CORPORATION or CALI-FORNIA,

Application filed April 2.9,

My invention relates to ieeans' for limit.-

ing the speed of a trai-n and tor automatically stopping the train ordecreasing the speed thereof when a. block section of rtrack precedingthe train is not in normal condition.

An object of the inv'ention is to provide an extremely simple andpositively acting electrically andv magnetically operated mechanismwhich will cause the application of the ytrain brakes when a blocksection of the track preceding the train is not in normal condition andthe train speed exceeds a predetermined value.

Another object of the invention is to pro,- vide means ot' the characterdescribed. which will cause the` application of the brakes when thetrain exceeds a. predetermined speed regardless ot the condition of thetrack preceding the train.

A further object of the invention is to provide means which willtemporarily render the automatic brake applying `mechanism inoperativeproviding the speed of the train is not in excess oli' .a predeterminedvalue. 1

still further object ot' the invention is to provide a single meansassociated with the track for causing the operation of the apparatus toeffect the foregoing objects.

rThe invention possesses other objects and features of advantage, someoit which, with the foregoing, will beset forth in the tollowingdescription oi' the preferred form of my invention which isxiliustratedin the drawings accompanying and forming part ot the sptciiication.` Itis to be understood that I do not limit .myself to the showing made bythe said drawings and description, as I may adopt variations of thepreferred orm within the scope of my invention as set forth in theclaims.

AUTOMATIG TRAIN CONTROL.

1924. Serial, No. 709,779.

ing train and track elements of the device.

In Figure 1 ot the drawings the portion shown above the track 2 isarranged Ito be carriedV on the train, while the portion included.between the rails -otthetrack .Y is

Y adaptedf to be held .inv substantially xed essociation with respecttothe track.v As here illustrated .the track comprises rails 3 and l andis divided into insulated block sections as in signal control systems,three of such sections 6, 'T and 8 being here represented. In thepresent embodiment, my invention is used inconnection with theair-brake-system of the train, and accordingly a well known ,type ofthis system is here diagrammatically illustrated and shown abovevtherepresenta- 4ion of the track. Included in the brake system is theengineers brakefvalve) connected to the air reservoir 1 2 by reservoirkpipe 13, andconnected .to the brake-pipe 14 bythe branch 15g. Asisusual the brakepipe communicates with the distributing valve andtriple valves on the cars ofl the train, the v'alvesbeing caused tobring about the applicationof the brakes when the pressure inthevlorakepipe decreases belowa predetermined point.

The brake-.valve is provided with a suitable control lever 17 cadaptedto be placed in various positions, such as release, running andlservice, the latter causing a reduction olf the pressure inthebrake-pipe and consequent application of the brakes. ln the presentarrangement the mechanism of my invention operates inconjunction withthe control lever of the brake-valve, and suitable mechanical actuatingmeans aretheretore associated with -said lever and adapted to ybeoperated by my automatic control means. The lever actuatingmeansincludes a cylinder 18 which islixedpositioned ad.- jacentthebrake-valve .and in which a. piston 19 is mounted for reciprocation.The latter is provided with a rod 21 which extends through the cylinder.head 22 and is adapted to reieasably 'engage the lever so as tomoye itto serviceposition.

Formedlin the cylinder so as tolie on opposite vsides' of the pis-ton invall of the posi@ tions thereof are ports 231 and 24 which by means ofthe pipes r2.6 and 27 aiord the cylinder communication with thereservoir and `brake-pipel respectively. The pipe 26 includes a ,valvek28 which normally CLI maintains suiiicient pressure in the portion ofthe cylinder Q9 associated with port 23 to exceed the pressure obtainingin the brakepipe. In this manner, under normal conditions, thepiston-rod will be held entirely released from the control lever, andthe latter may be manipulated at will. However, should the pressure inthe chamber 29 be reduced below the brake-pipe pressure, the piston rodwill be moved to place the lever in service position and an applicationot' the brakes will result.

Accordingly, therefore, means are provided for automatically causing areduction of the pressure in the chamber 29 when a train` travelling inexcess of a predetermined comparatively slow speed approaches a tracksection which is not in normal condition. As here shown, said meanscomprises a pipe 3l which communicates at one end with the chamber 29and at the other end with an electro-magnetically operated applicationvalve 32. The latter includes a valve stem 33 in the form of a magneticcore which is associated with a magnet coil 34 and is arranged tocontrol the flow of air through t-he valve. When the coil is energizedthe core closes the valve passage 35; however, when no current iowsthrough the coil the core may be displaced by the pressure of air inpipe 31 and t-hereby permit the air to escape through outlet 36 and thusrelieve the pressure in chamber29. The coil 34 is arranged in a normallyclosed circuit 37 containing a suitable source of current such as thebattery 37. Associated. with the circuit 3T and arranged in lparallelwith each other and the roi 34 is a plurality ot longitudinally, alignedmagnetically operated gravity switches 39 contained in shortcircuitingbranches 4l. offering low electrical resistance compared with the coil34. Each of the switches includes an. armature 43 which is normally heldraised. 'trom engagement with a cooperating contact member 44 formingpart ot' the circuit 37 by means o't the attraction of a relatively weakbar inag net 46 which is strong enough to hold the armature, but notstrong enough to raise it from its lower position. it will now be understood that if either or both armatures are caused to engage contactmember 44, the current will be diverted from the coil 34 through abranch circuit 41 and back to battery 37 with the result that the core33 will become demagnetized, and the pressure in the chamber 29 may berelieved to bring about an application of the brakes. lt will new benoted that with switches 39 all open, the current from battery 37 willpass through conductor 37a, will be divided between the contact member44 and a similar member hereinafter more particularly referred to andwhich is connected in parallel with the member 44, and will then passthrough conductor 37b, coil 34, and back to battery through conductor37C. On the other hand, when one or more of the switches 39 is closed,the major portion ot the current from battery 37 will pass throughconductor 37a to contact member 44, through the member 44 to the closedswitch or switches 39, through the branches 4l, and thence back tobattery through conductor 37C, thus so weakening the current through thecoil 34 that the valve 32 will be permitted to open. Means are providedtor causing' the armature 43 to be moved into contact with the member 44against the resistance of the magnets 46, when the track sectionpreceding the train is not in normal condition. such means beinginoperatively disposed with respect to the switches 39 when trackconditions are normal. As here shown, said means comprises a relativelystrong' magnet 47 associated with each track section and arranged to bemoved transversely trom one position to another so that when the trainpasses thereover the armatures 43 will or will not be aitected therebyin accordance with the condition of the preceding track section. Each otthe track magnets, as here illustrated, is ot the permanent horseshoetype and is mounted on a carriage 43 arranged on an inclined runway 49.The carriage is preterably arranged between and is adaptedto movetransversely of the track rails.r The switches 39 are so positioned onthe train that when. the train passes b v the track magnet while thecarriage is at the higher end ot the inclined runway, the switch magnets46 and associatedv armatures 43 will pass transversely of the magnet 47at such distance as not to be appreciably affected tl'iereby, whereas.;with the fmagnet Lcarriage positioned at the lower endet the runway, oney pole ot the switch magnet 43 will pass over in close proximity to atrack magnet pole ot like polarity. In the latter event, it will beevident that while the niagnet poles are passi ng. the attraction ot theswitch magnets 46 ter the armatures 43 will be neutralized and thearmatures will be moved by gravity and the excess attraction of thetrack magnet to engage the Contact member 44, thereby eitecting thesetting of the brakes in the manner preif'iously described.

The proper positioning of the track magnet in accordance with trac-kconditions is here shown effected through the agency ot a motor 5l andan electro-magnetic clutch 52 mounted upon a shaft 53 driven through aworm 54 and wheel 55 by the motor. Carried on said shaft for relativerotative movement thereon is a sleeve 57 which is fixed to a drum 5Sabout which is adapted to be wound and unwound a cable 59 attached tothe tr ck magnet. Connection between the shaft and sleeve is effected bymeans of the clutch, the winding 61 thereof being ar- LOU izo

ranged on the sleeve While the' magnetic plate or armature .62- carriesthe Wheel 55. Che motor and clutch are connected in series in ascii-cuitvhaving a suitable source of current such as the battery Gel andprovided with a switch 66 whichA is normally retained in closed positionby means ot'the track relay 67. A suitable resistance 68 is alsoarranged in circuit 63 s o `th at Aunder normal Yconditions the currentWill be merely suficient to hold the clutch engaged but not enough torotate the motor shaft. The sleeve and drum vare held in such relationto the motor shaft, thatv With the track clear and the circuit 63 Yclosed, the carriage and magnet Will be held vwhich is connected inp'arallelvf'ith the resistance 68. As shown in Figure 4, the circuitbreaker comprisesa broke-n conductor ring 70a carried onthe sleeve 57and insulated therefrom, brushes 70" being utilized to provide thenecessary contact therewith. When the magnet is inoperatively disposed,the circuit breaker is likewise positioned; hoivever, When the magnet isin operative position the circuit breaker complet-esa shunt around theresistance.

soon as the track returns-'to normal condition and the circuit 68 againbecomes closed, practically the full line current will pass through themotor and the shaft of the lat-ter ivil be roitated. Rotation of themotor shaft Will continue until the track magnet has been moved'to Aitsinoperative position,

Vativhich time', as above explained, the circuit breaker Will open theshunt and themagnet Will be thus lleft in saidr latter position.

It will, now be noted thatxthe rails 3 and e oitv each track. section orblock form part of a constantly closed track. circuit containing a trackrelay 67 and a battery l0, and that the relay 67 of each section circuitis arranged to operatev the switch 66 of a section behind it. Thus, asherein particularly shown, the track magnet and mechanism positioned" invthe track section 7 is particularly arrangedfto be controlled from thetrack section 8,', it being noted that Whena y tra-iu is positioned inthe section 8, circuits Willbe provided through its setso-f Wheels andaxles to electrically connect theiailsA and thereby short out theportionofthe track circuit containing the'relayl Gftof allow the openingjofthesgivit'ch. In thisqm-anner, the switch (361*iivi'llbe caused teremainopen In this manner until the train leaves the block 8 so that anytrain attempting toentcr the block 7 While a train isy in block 8Y Willhave its brakes -automat-icallyl set in the manner vhereinbeforedescribed..v Itv Will now be noted' that when the4 train lea-ves vblockr8,'th`e normal current flow through the track relay will 'be resumedtojthereby'fc-lose the correspondshown the device-otm-y inventionapplied to a Vone-Way tracky to'provide -control of a iollowingv "trainYfor only one Yblock behind a leading train, itwill be obvious thatcontrol. for a two-Way track lor ter more than one track magnet behind atrain merely requires the duplicati-on of the Imagnet positioningmechanism and an appropriate system otin Y terconnected trac-k relayssimilar to those nowv used in block signal systems. will also be notedthat the various mechanisms of the device are illustrated throughout'asin the condition of lno-rmal'running oi va train With the track sectionsin proceed condition, the different controlv positions being describedin detail lie-rein in connectionY with the description ofthe variousoperations of the device'. l

In the even-t that theautomatic control d' mechanism on the train inpassing over the track magnet, operates to cause the setting of thebrakes, lthe.` latter may only be released' upon the engineer' raisingthe armatures 43' by hand, whereupon the valve B'is rcseated.` thepressure in'pressure chamber 29 builds upagain andthe piston rod isWithdrawn from operative engagement with :the control lever of thebrakevalve toa'llovv'the engin-eer to release thc'brakes.

Means are provided'fortemporarily rendering the automaticsbrake-applyingmech* anism inoperativeproviding the speed of the train is not in excessof ay predetermined value. Fed with airfrom the main reservoir 13'through a restricted-port-valve 70, is a volume 'tank 71 which is'vadapted to contain a comparatively limited amount of air underpressure. The volume tank is in turn connected with anelectro-magnetically operated pressurevalvel which is providedwitha stem73 arrangedto 'be actuated by the magnet Corelli".v The valve is: provided vvvith a passage 75 which is: normally kept shut byV means of aspringpiress dvalrc element 76C Opening ofthe passage 751 is effected byenergizing the magnet coil 77 in which the core 74v is arranged, thevcoil being contained in an electric circuit 78 which includes' asuitable'source of current such as a battery 1"8.y The passage 75 isconnected'ivith a pistonvalve Z9-into which the/air from the passage isarrangedto dis.- cliarg'e when the' valve element 76 is open. Therpstenvalve includes@ pistoni 80'- to 'iuO which is liXed a rod 8l havingpreferably secured thereto a contact 82 which is adapted upon thedisplacement ot the piston 8O to bridge a pair of lspaced contactele-ments 88 arranged in an electric circuit 84 having a suitable sourceot' current such as the batteries 84 included therein. Contained `in thecircuit 78 and positioned to lie at the 'front and rear of the switches89 are gravity switches 86 ot the same type as are the switches 89, eachof which in the present embodiment ot the invention comprises a bar 87which is normally magnetized but possesses insutlicient magneticstrength to draw a pivotally mounted armature 88 thereto and therebycomplete the circuit 78 through the armature and a contact 89. Theswitches 86 are thus also arranged to pass over a pole of the trackmagnet when the carriage ot the latter is in operative position, or inother words, when the track section ahead ot the train is not clear. Thepoles ot the bar magnet 87 and track magnet 47 which are arranged tocooperate are ot unlike polarity, so that as the weaker magnet 87 passesover the relatively strong pole of the track magnet, an increasedmagnetic strength will be induced in the magnet 87 and the armature willbe drawn upwa-rd thereby to close the circuit 7 8. It will be noted thatthe pivoted switch armature 88 is arranged to normally lie in a support90 and is held close enough to the contact 89 thereby as to insure itsraising as the track magnet passes thereunder. The closing ot circuit 78being thus elfected by the drawing ot the armature 88 against thecontact 89 will now cause the opening ot the valve 72, so that thecontact- 82 will be moved against the contact elements 88 to close thecircuit 84 in the previously described manner. The circuit 84, it willnow be noted, also has electro-magnet coils 85 included therein, each otsaid coils being preferably arranged t-o encircle the bar magnet 46 of aswitch 39 and being capable,` when excited, ot increasing the pull ofthe magnets 4G to prevent the engagement or armatures 48 with .members44 against the pull. of the track magnet. The circuit 84 also provides abranch circuit around the coils 85, and which circuit is arranged tosimultaneously energize coils similar tothe coils 85 for a purpose to behereinafter more fully described. Assuming, then, that the track is notclear and that the train has passed over the track magnet to close theswitch '86, current will flow through coil 77- and air will be forcedinto the piston valve 79 to ett'ect the closing ot circuit 84, thuspreventing the automatic application ot the brakes. lt will be noted byreferring to Figure l that the valve 79 is provided with a relief port91 which is adapted to be uncovered by the piston on its forward stroke;by varying the position and size of said port the duration and time otclosing and opening of the circuit 84 'may be readily predetermined.Furthermore, relative positioning of the switches 86 and 39 must be suchthat when the train is traveling at a speed not greater than thepermissive speed, the coils 85 will have been energized by the time theswitches 89 pass over the track magnet to thus prevent the applicationof the brakes in the manner indicated; whereas, it the train is movingat a greater than permissive speed, the brakes will be automaticallyset. In this manner. a train may be allowed to proceed into an adverseblock, but only when going slowly enough topermit its stopping within ashort distance, the mechanism thus` providing what may be convenientlytermed a cautionspeed control.

lVith the circuit 78 closed at the switch 86, the current Jfrom battery78 will flow through conductor 78il to and through the switch 86, thencethrough conductor 78b to and through the operating coil 77 ot the valve72, and thence back to battery 78 through conductor 78". When circuit 84is closed between contacts 83, its current will tlow from the battery 84through conductor 84n to a contact 83, thence through the bridge contact82 to the other contact 88, thence through a conductor 84h to the coils85 which are here shown connected in series, and thence back to battery84 through conductor 84` p soon as a magnet 86 has passed over the trackmagnet, the armature thereof will drop to thereby break the circuit 78at Contact 86, and thus allow the closing of valve 72, whereupon thepiston 8O will tall by gravity las the imprisoned air escapes fromthereunder and the bridge contact 82 will be drawn away trom thecontacts 88to break the circuit 84,

Means are also provided in connection with the mechanism just described:tor insurw ing an application of the brakes in case said mechanismfails to properly function or release, as for example, it the circuit 84should not become broken within a reasonableV pe-` riod after theswitches 89 pass over the track magnet. As here illustrated, said meanscomprises a differential-piston-valve 92 providing a cylinder 93 havingbore portions of different diameters at opposite ends thereof. The boreportion of smaller diameter is connected to the pipe 3l, while that withthe larger' diameter is connected to the volume tank 7l. Mounted in thesmaller and larger cylinder bore portions respectively are pistons 494and 95, such pistons being fixed together in spaced relation wherebythey may be simultaneously disposed in corresponding parts of theirbores. Normally, Y

the

It will now be noted that asV as indicated in Figure 1, the pistons lieat opposite sides ota relief p0rt97 formed inl the cylinder with thepiston 9,5. ,disposed/at the inner end; of its stroke and the ,piston 91disposed ,at the outer end of its stroke; how' ever, should either vofthe armatures lS8 fail to become disengaged from the magnets 87 andthereby leave the circuit 84 indefinitely closed,.the pistons 9a and9.5, by reason of` munciation with the 'cylinder at the outer side ofVthe piston 91 and the pressure in the chamber 29 vwill be relievedthrough port 97 to e'ect the automatic application of ther brakes..

Means are also included for `causing the automatic application ol'f thebrakes when the track section preceding the train is clear butthe trainexceeds a predetermined maximum speed. As here shown, said means areadapted to be actuated by means associated with the track, and, in fact,are arranged to be lactuated by the same track magnet 47 which operatesthe train brakes when the track is lnot clear. Connected in the .circuit84; in parallel lwith theswi-tches 39 therein and operable similarlythereto ris a plurality of switches 101., v.while switches102, .adaptedto operate similarly to the switches 86, are

arranged in parallel with .the latter in thev circuit 7 S. Switches 101and 102, it will be noted, are arranged in alignment longituf dinally of.the train with .the former between the latter land :are so positionedtransversely of the switches 39 and vS6 that they may be affected bythetrack magnet only when the latter is positioned in the upper or clearposition. The switches 101 and 102, it vwill b e noted', respectivelyinclude bar magnets 103 and 104 land pivoted armatures 106 and 107, thearmatures 106 being, arranged to contact, when displaced downwardly,with a common contact member108j connected in the circuit .of `battery.37 in parallel with the contact 441-, while the arma.-

' tures 107 are` arranged to contact v,with

switch contacts 102 when moved upwardly,

the. armatures thus being similarly operable to those of the switches139 and :86 respecf tively. Coils 10.9 are mounted on magnets 103, suchvcoils being similar to and connected in parallel. with the coi-ls 85.

By reference-to. Figure `5, it will be noted that with the track magnet17 in iltslower, or adverse, position, as sho-wn in Adotted lines, onepole'111 thereofis arranged rto lie ink a common vertical plane with theswitches 39 andl 80, while the other pole 112 of. the magnet will lie ina .common verticalplane with the vswitches 101'and 102. `It will now vbefurther noted :that with. the magnet pole-111 having .a given polarity,.the lower poles of the .magnets 16 of the switches BQvmuSt have a' likepolarity thereto, while the lower poles of' the magnets 8 7' of theswitches 86 must have an opposite .polarity therefrom, in order toinsure the desired operation of the device. Onjthe other hand,the'switches 101 and l102 mustr ber inoperative under adverse trackconditions, which result is simply accomplishedby havingl the polaritiesof the lower poles of their magnets the same as those .of'magnets 46 and87 respectively, so

that the' polarity ofthe pole 112, which is v obviousl-y the opposite ofthat of pole 111, may positively Vprevent the operation of the switches`as the pole 112 passes thereunder, by respectively vneutralizing andstrengthening the polarities of the magnets 104 and 103.

VVllhen. the track magnet 17 is in its normally raised, or favorableposition, as show n in full lines in Figure 5, the pole 112 thereof willbe laterally displaced from both sets of switches, and therefore cannotsufciently influence them .to cause .their actuation.

The pole 111, however, will now bel inpfosiy tion to effect theoperation of the switches 101 and 102, and since the polarity relationswill be the same as when the pole 111 Was in position to cooperate lwiththe Vswitches 39and- 8.6 for y their actuation, corresponding operative,effects .will be obtained. It will now be noted that in. the latterinstance, the spacing .of adjacent switches l101 and 102 will ,be'madesuch. as toallow thek operation of Ithe trainhat ,any speed up to theallow'- able maximum,;thus providing what might be .termeda full-,speed.control in contradistinction tothe caution-speed control affordedthroughy the switches39and 86. A

By providing more than oneof' each of the switches i39and101 4operationof the de.- vice is assured, Yit-loeing evident that the properoperation of' any ,one of l these switches will short outthelcircuit 3 7and thereby cause the setting lof -,the brakes. Switches'S-or 102 shouldbe positioned both ahead .of rand bolliillffl the, SN-Trimbos .'39 plld101 respectively toyallow reverse .operation oit the'train .on-a -trackarrajin-'ged `tor @two-V waycontgrol, since one of.the.;torn-ierv mustoperate aheadof the latter fwi-thwghich it is associated in order toprevent setting of the brakes.v 4 Y Y ,ltr-will nowlievevident that amechanism has been provided: which. will not .only cause l train, apermanently magnetized track magried on the train adapted to be actuatedbyV said track magnet to eii'ect an application of the air brakes when asection preceding the train is not in normal condition, andelectromagnetically operated means carried by said train and adapted tobe actuated by said magnet to prevent. the application of said brakes bysaid lirst means when the train in approaching said section istravelling below a predetermined rate of speed.

2. In an automatic train control, the combination with a series otinsulated track sections and an air-brake-system carried on the train, apermanently magnetized displaceably mounted track magnet associated witheach of said sections, means on said train adapted to be actuated bysaid track magnet for effecting an application or' said brakes when atrack section preceding the train is not in normal condition, and meansadapted to be actuated by said track magnet to prevent the applicationof said brakes by said iirst means when the train is approachingr saidsection below a certain rate of speed.

3. ln an automatic control for trains, the combination with a series ofinsulated track sections and an air brake system carried by the train,of Va displaceable track magnet associated with each track section,means operative to displace a track magnet when the associated tracksection is not in normal condition, means carried on the train operativeto effect the application of the air brakes by and only when the trainpasses a displaced track magnet, and means carried on the trainoperative by said displaced magnet to prevent the application of saidbrakes by said preceding means providing the speed of the train is belowa. certain rate.

el. In an automatic train control, the combination with a brake-systemand a series of insulated track sections, a magnet associated Awith eachsection, electromagnetically operated brake controlling means comprisingan electric circuit, a magnetic switch in said circuit adapted to beactuated by a magnet, and a second switch, and an electric circuit inwhich said second switch is contained adapted to magnetically influencesaid first switch and thereby prevent the ac tuation thereorp by a trackmagnet.

' 5. An apparatus in accordance with claim 4l characterized by thesecond switch being positioned for actuation by a track magnet.

6. In an automatic train control, the com bination with a series ofinsulated track sections and an air-brake-system carried on the train, atrack magnet associated with each of said sections, means on said trainadapted to be actuated by a track magnet for elect ing an application ofsaid brakes when a track section preceding the train is in ad versecondition, means adapted to be actuvk plication ot the brakes under saidlatter condition in case said last means fails to allow the applicationof the brakes by said iirst means after preventing said application fora certain interval.

7. In an automatic train control, the combination with a brake-systemand a series of insulated track sections, a track magnet movable toassume different positions when the track is in normal andadverse'conditions, means operative by said track magnet to cause theactuation of the brakes when the track is in adverse condition, meansoperative by said track magnet to cause the actuation of the brakes whena predetermined speed is exceeded by the train regardless of thecondition of the track, and means operative by said track magnetregardless of thecondition of the track to render inoperative said brakeactuation means when the train is travelling below a predeterminedspeed.

8. ln an automatic train brake control, the combination with an airbrake valve and a series of insulated track sections, a track magnetmovable transversely of a track section to assume ditlerent positionswhen the track is in normal and adverse conditions,

means operative by said track magnet tocause the actuation of the airbrake valve to set the brakes when said track is not in normalcondition, means operative by said track magnet to cause the actuationof the air brake valve to set the brakes when a predeterminedspeed isexceeded, regardless ol the condition of the track, and means operativeby said track magnet to render inoperative said air brake actuationmeans when the train is travelling below a prede termined speed.

9. ln an automatic train brake control, the combination with an airbrake and a series of insulated track sections, a track magnet movabletransversely of a track section to assume different positions when thetrack is in normal and adverse conditions, and means operative by saidmagnet to cause the application of the brakes when a predetermined speedis exceeded by the train when said magnet is in either of said,'pfositions.

10. In an automatic train control, the combination with an air brake anda series of insulated track sections, a track magnet movable to assumedifferent positions when the track is in normal and adverse conditions,and means operative by said magnet to cause the application of thebrakes when lll) maximum speed, or it tlie track is in adversecondition, the train is travelling under a predetermined minimum speed.

12. In anautomatic train control, the combination' with a brake systemand a series of insulated track sections, magnets arranged in saidsections, electro-magnetically operated means carried on the trainadapted to be actuated by said magnets to effect an application of thetrain brakes Y' when the track is not clear, electro-magnet# icallyoperating means Carried by the train adapted to prevent the actuation ofthe brakes by said means providing the train is travelling below apredetermined minimum speed, elect-romegnetically operating meanscarried by the train and adapted to be actuated by said magnets forcausing an application ot the brakes regardless of track con* ditions,and electro-magnetically operating means carried by the train adapted tobe actuated by saidl magnets to prevent the application of the brakes bysaid last means providing the speed of the train is below apredetermined Vmaximum value.

13. In an automatic train control, the combination with a l brake systemand a series ot insulated track sections, a track magnet associated witheacli section adapted to lie in different positions when the associatedsection is in normal and adverse coiiditions, electro-magneticallyoperated means carried on the train adapted to be actuated by one ofsaid track magnets to effect an application of the brakes when themagnetis'in the position occasioned by adverse track conditions,electro-magnetically operated means carried on the train arranged to beactuated by said magnet to prevent the application of the brakes by saidfirst means providing the speed of the train is below a predeterminedminimum value,

electro-magnetically operated means carried on the train adapted to beactuated by said magnet tc effect an application of the brakes when themagnet is in the position occasioned by normal track conditions, andelectro-magnetically operated means carried on the traink adapted to beactuated by said last mentioned means providing the speed l of the trainis below a predetermined maximum value. i

14. In an automatic train control, the

combination with a brake-system, track magnets, electro-magneticallyoperated brake controlling means comprising an electric circuit,normally inoperative means adapted to be actuated by a track magnet toshortcircuit said circuit, a switch, and an electric circuit in whichsaid switch is `contained adaptedto iniiuence said means to preventthe-actuation tliereotby track magnet.

15. In an vautomatic train control, tlie combination with abrake-systemrcarried o n the train, track magnets, means on said ltrainadapted to be actuated by a track magnet tor effecting an application ofsaid brakes, means adapted to be actuated by a i track magnet to preventthe application ot said brakes by said first means when the train isapproaching said section below a predetermined maximum rate oi' speed,and means opera-tive to cause an application of the brakes under saidlatter condition in case said last means fails to allow the applicationot the brakes byv said rst means after preventing said application 'fora certain interval. In testimony whereof, I have hereunto set my hand atOakland, California, this 16th day of April, 1924.

. THOMAS M. RIGGLE.

